There’s a huge market for 433 MHz alarm system hardware out there ... that pulled them all together into a complete home automation system on the cheap.

An AVR chip running the Arduino bootloader monitors a phototransistor ... [Fileark] was inspired to build his after seeing the alarm-clock coop door. We don’t know if he got a chance to look ...

The alarm only stops when you press the push ... to monitor for light sources from other directions. Making an Arduino-powered automatic trash bin that opens and closes the lid for you is a ...